1. Field of the Invention
The present invention relates generally to an apparatus for separating individual fibers from a fiber aggregate. More specifically, the invention relates to an apparatus for separating fiber, such as carbon fiber made from coal pitch, from a mat-form or candy fluff-form fiber agregate for enabling use of individual fibers in independent form. And more particularly, the invention relates to a method for producing fiber-reinforced concrete or fiber-reinforced gypsum material, in which a supply of carbon fibers separated from the aggregate is integrated.
2. Description of the Background Art
Fiber, such as carbon fiber, is known to be a good reinforcement material. For example, carbon fibers are utilized for forming fiber-reinforced concrete or fiber-reinforced gypsum board. On the other hand, carbon fiber can be produced from various materials in various ways. For example, carbon fiber can be produced from coal pitch, this type will be hereafter referred to as "coal pitch carbon fiber". Such coal pitch carbon fiber is cheap to produce and thus is advantageous to use in various fields from the viewpoint of cost. However, on the other hand, such coal pitch carbon fiber has relatively short fiber length and is produced in forms of a candy fluff-form or mat-form aggregate. Such fiber aggregate tends to become unevenly distributed within the concrete or gypsum and thus leading to non-uniformity of strength within the concrete or the gypsum board to be produced.
On the other hand, there are various ways for producing long carbon fibers. When long carbon fiber is used for forming the material for fiber-reinforced concrete or gypsum, the carbon fiber is cut into lengths of 5 to 10 mm. Since carbon fiber has a diameter of 8 to 80 microns and a specific gravity of 1.2 to 1.9, the cut fiber tends to aggregate during cutting operation or during packaging. Therefore, even using the long fibers, the same or similar problems arise when forming the material for the concrete or gypsum.
In order to solve the aforementioned problem, a method is proposed for separating the individual carbon fibers from aggregate and supplying them to concrete, mortar, gypsum and so forth, in Japanese Patent First Publication No. 58-181760. In the proposed method, a plurality of needle like projections are provided on opposing surfaces of movable members. The carbon fiber aggregates passes through the spaces between the projections of the movable members which are positioned to overlap opposing set projections. The overlapped projections serve as a comb for separating individual fibers from the aggregates. However, this proposed system cannot completely separate the individual fibers and thus is not suitable for practical use.